Gas combustion device

ABSTRACT

A gas combustion device  1  is provided with combustion chambers  11, 13  for burning gas supplied from a gas source therein and a combustor  7  with a combustion gas vent  37  for discharging combustion gas burnt in the combustion chambers. The combustion gas vent  37  is provided with a baffle member  41  for adjusting distribution of the combustion gas discharged from the combustion gas vent  37.

TECHNICAL FIELD

The present invention relates to a gas combustion device for generatingcompletely burnt hot air or warm air with high combustion efficiencyusing burning flame caused by, in particular, Liquefied Petroleum Gas(LPG) as a heat source.

BACKGROUND ART

Conventionally, a gas combustion device contained in devices such asportable hair driers and heat guns has been known.

In a gas combustion device contained in a hair drier, for example, acombustor for burning combustion gas (for example, LPG) is provided in acylindrical casing of the hair drier. The combustor bums the combustiongas supplied from a gas tank as a source for the combustion gas and theair heated in a combustion chamber of the combustor is emitted to theside of a vent by a fan provided at the side of an inlet of the casing.

LPG as combustion gas is supplied from the gas tank to an ejectorprovided at the combustor. In the ejector, outside air necessary forcombustion is sucked and mixed gas which consists of the combustion gasand the sucked air is generated. Thereafter, the mixed gas is injectedfrom a wick (wire mesh) provide at the side of the inlet of thecombustor. A spark is blown from an ignition plug (ignitor) to the wickand ignites the mixed gas.

The ignited burning flame burns in the combustion chamber so as tospread outwards from the wick and the combustion gas is discharged froman opened vent for combustion gas at an end ahead of the combustionchamber as warm air (refer to Japanese Patent Application Laid-openPublication No. 2002-233416).

In the conventional gas combustion device, the temperature of thecombustion gas generated from the combustor tends to become high at itscenter part and low at its peripheral part. Especially when the gascombustion device is used for the hair drier or the like, outside airsent from an air-blower such as the fan provided at the hair drierpasses laterally to the air heated by the combustor, causing the problemthat the temperature of warm air at the center part becomes higher andthe temperature of warm air at the peripheral part becomes lower.

Furthermore, when a large amount of the combustion gas is generated fromthe combustor, hot combustion gas and burning flame along with the airsent by the fan are easy to directly burst out of the combustor, causinga safety hazard.

To solve the above-mentioned problem, the present invention intends toprovide a gas combustion device in which the temperature of warm air ofthe combustion gas discharged from the combustor is uniformed and whichhas high safety by preventing burst-out of burning flame.

DISCLOSURE OF THE INVENTION

To achieve the above-mentioned object, a gas combustion device comprisesa combustion chamber for burning gas supplied from a gas source therein,a combustion gas vent for discharging combustion gas burnt in thecombustion chamber, and a baffle member for adjusting distribution thecombustion gas discharged from the combustion gas vent which is arrangedat the combustion gas vent.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional view of a gas combustion device in accordance withan embodiment of the present invention taken along a line I-I in FIG. 2.

FIG. 2 is a front view of the gas combustion device viewed from the leftside in FIG. 4.

FIG. 3A is a plan view of a baffle plate in accordance with theembodiment of the present invention.

FIG. 3B is a side view of the baffle plate in accordance with theembodiment of the present invention.

FIG. 4 is a side view of the gas combustion device in accordance withthe embodiment of the present invention.

FIG. 5 is a sectional view taken along a line V-V in FIG. 1.

FIG. 6 is a back view of the gas combustion device viewed from the rightside in FIG. 4.

BEST MODE FOR CARRYING OUT THE INVENTION

Referring to figures, an embodiment of the present invention will bedescribed below.

With reference to FIG. 1, a gas combustion device 1 in accordance withthis embodiment has an ejector 3 for generating mixed gas consisting ofLPG, for example, as combustion gas and air, an electrode 5 as anignitor for igniting the mixed gas generated by the ejector 3 and acombustor 7 for burning the mixed gas ignited by the electrode 5therein.

Referring to FIGS. 4 to 6, a chamber 9 of the combustor 7 made ofaluminum (die-cast) is a substantially cylindrical body with circularright and left side faces in the longitudinal direction of the chamber 7in this embodiment as shown in FIGS. 5 and 6. The inside of the chamber9 is comprised of a primary combustion chamber 11 located on the rightside in FIG. 1 and a secondary combustion chamber 13 located ahead ofthe primary combustion chamber 11 (left side in FIG. 1). The ejector 3is attached to the gas induction side in the rear of the primarycombustion chamber 11 (right side in FIG. 1).

The ejector 3 is provided with a nozzle 19 for injecting gas suppliedfrom a gas source such as a gas tank (not shown) for storing combustiongas such as LPG through a gas supply pipe 17 as a gas passage at theside of an inlet of a substantially cylindrical ejector body 15 having acircular cross section (right side in FIG. 1). A pin hole as aninjection hole (not shown) having a bore diameter of φ60 μm to φ200 μm,for example, is provided at a front end of the nozzle 19. The injectionhole is an orifice formed substantially in the center of a disc-likepin-hole disc (not shown) and LPG is thinly discharged at high speedclose to sonic speed. A filter (not shown) for removing impurities anddusts which block the injection hole is provided in the nozzle 19. Forexample, a sintered metal with a pinhole having a diameter of 10 to 30μm is used as the filter.

A mixer 21 for mixing the combustion gas (LPG) with a primary air andintroducing the mixed gas into the combustor 7 is provided in theejector body 15 ahead of the nozzle 19 and a primary air hole 23 forsucking the primary air penetrates a side wall of the mixer 21.Accordingly, the pressure in the mixer 21 becomes negative due to thecombustion gas (LPG) discharged from the nozzle 19 at high speed, andthe primary air is sucked from the outside. The sucked primary air issent to a forward wick 25 as a gas combustion part while being mixedwith the discharged combustion gas. This is called as an ejector effect.By adjusting area of the primary air hole 23, the ratio of the primaryair can be adjusted.

The wick 25 as the gas combustion part is a cylindrical SUS metal meshof 50 to 150 mesh, for example. The wick 25 is attached to the end aheadof the ejector body 15 by welding or the like substantially in thecenter of the right half of the primary combustion chamber 11 of thecombustor 7 in FIG. 1. A wick holder 27 as a direct-advance suppressionpart is attached to the end ahead of the wick 25 by welding or the like.

The mixed gas discharged from the mixer 21 is guided mainly laterally(the direction shown by an arrow AR1 in FIG. 1) by the wick holder 27and the mixed gas of the combustion gas (LPG) and air is discharged fromthe mesh of the wick 25. The flame after ignition is blue andsubstantially circular.

The electrode 5 is provided within the combustor 7 and ahead of the wick25 and in the vicinity of the side face of the wick 25. High-tensionelectricity generated in a piezoelectric element for ignition (notshown) is input to the electrode 5 through an electric wire 29 and aspark is blown from the front end of the electrode 5 to the wick 25. Thespark ignites the mixed gas discharged from the wick 25, thereby burningthe mixed gas.

Referring to FIG. 5, on an inner wall of the primary combustion chamber11, a plurality of groove parts 31 extending in the forward-rearwarddirection (horizontal direction in FIG. 1) are radially arranged aroundthe wick 25. In FIG. 5, six groove parts 31 are formed.

A plurality of secondary air holes 33 for supplying outside air(secondary air) to the primary combustion chamber 11 are provided on arear wall (right side wall in FIG. 1) of the primary combustion chamber11. The plurality of secondary air holes 33 are disposed so that thesecondary air is supplied to the mixed gas after ignition at theposition other than an ignition point. The ignition point means the areawhere a spark generated by the electrode 5 can reach at the side of theelectrode 5 in the periphery of the wick 25 as shown by an areasurrounded by a dotted line in FIG. 5. In this embodiment, fivesecondary air holes 33 are provided.

A plurality of tertiary air ducts 35 as tertiary air holes for supplyingoutside air (tertiary air) to the secondary combustion chamber 13 areprovided in the wall of the primary combustion chamber 11 betweenadjacent groove parts 31. In this embodiment, six tertiary air ducts 35in total are provided.

A front end of the secondary combustion chamber 13 is opened and theopening forms a combustion gas vent 37 for discharging the combustiongas burnt in the secondary combustion chamber 13.

A plurality of fins 39 for heat exchange are provided in the outerperiphery of the chamber 9. The fins 39 has the effect of emitting heatgenerated when the mixed gas is burnt in the chamber 9 and cooling thechamber 9, that is, performing heat exchange.

Next, a baffle member forming a main part of the embodiment of thepresent invention will be described.

Referring to FIGS. 1 and 2, a baffle plate 41 as the baffle member is apartition for adjusting distribution of the combustion gas dischargedfrom the combustion gas vent 37 and attached with a claw part 43 whichprotrudes from the end face of the chamber 9, for example, so as tocover the whole of the combustion gas vent 37.

As shown in FIGS. 3A and 3B, the baffle plate 41, the periphery of whichis substantially circular, is shaped like a circular disc and notchedparts 45 each engaging with the claw part 43 are provided on fourpositions on the periphery. The baffle plate 41 is comprised of a centerdischarge hole 47 provided at about the center thereof and peripherydischarge holes 49 provided on a virtual circle 51 surrounding thecenter discharge hole 47.

The center discharge hole 47 controls the direction of discharging thecombustion gas so that the combustion gas in the secondary combustionchamber 13 is discharged from about the center of the combustion gasvent 37. The periphery discharge holes 49 control the direction ofdischarging the combustion gas so that the combustion gas is dischargedfrom the part close to the inner wall of the secondary combustionchamber 13. In this embodiment, the center discharge hole 47 is asubstantially circular through hole provided at about the center of thebaffle plate 41 and the periphery discharge holes 49 are four elongatedholes provided along the virtual circle 51 near the outer periphery ofthe baffle plate 41. The center discharge hole 47 is smaller than theperiphery discharge hole 49 and most of the combustion gas is dischargedfrom the periphery discharge holes 49.

The shape of the center discharge hole 47 and the periphery dischargeholes 49 is not limited to the above-mentioned shape. For example, theperiphery discharge holes 49 may be serially arranged along the virtualcircle 51 near the outer periphery of the baffle plate 41 as a lot ofcircular through holes or may be formed in the other shape. The centerdischarge hole 47 may be formed to be smaller, formed as a plurality ofholes or formed in the other shape.

With the above-mentioned configuration, when LPG is supplied into thenozzle 19 of the ejector 3 through the gas supply pipe 17, LPG passesthrough the filter in the nozzle 19 and injected from the injection holeas the orifice to the mixer 21 at the speed close to sonic speed. As aresult, the pressure within the mixer 21 becomes negative due to theejector effect and the primary air necessary for combustion(corresponding to the air-fuel ratio) is sucked from the primary airhole 23 and flows into the mixer 21. And then, the flowed primary airand LPG are mixed to form the mixed gas and the mixed gas is injectedinto the forward wick 25.

In the mixer 21, in proportion to increase or decrease in LPG, theprimary air necessary for combustion is automatically sucked.Furthermore, by making the diameter of the primary air hole 23 small todecrease the amount of the primary air, the mixed gas with goodignitability is injected to the forward wick 25.

Since the wick holder 27 is provided at the forward end face in the wick25, the combustion gas (mixed gas) is mainly injected from the SUS metalmesh on the side face to the periphery.

Next, by supplying high voltage from the piezoelectric element forignition through the electric wire 29, a spark is generated from theelectrode 5 in the combustor 7 and surely ignites the mixed gas withgood ignitability emitted from the wick 25. Most of burning flamespreads outwards in a circle pattern from the side face of the wick 25and the length of the burning flame remains to be ten-odd mm from thewick 25. Warm air is transmitted along the inside of the primarycombustion chamber 11 and six groove parts 31 on the inner wall to theforward secondary combustion chamber 13.

At this time, since area of the primary air hole 23 is decreased tolower the ratio of the primary air, the mixed gas emitted from the wick25 has good ignitability because of high gas ratio. Since the secondaryair is supplied to the combustion gas after ignition from the secondaryair hole 23, combustion efficiency of the gas in the primary combustionchamber 11 is improved, thereby improving combustion performance.

Furthermore, since outside air of much cooler than the mixed gas duringcombustion (tertiary air) passes through the six tertiary air ducts(tertiary air holes) 35, the temperature at the wall part of the primarycombustion chamber 11 is effectively decreased. While the tertiary airsupplied from the outside cools the wall part of the primary combustionchamber 11, the tertiary air exchanges heat with the wall part of theprimary combustion chamber 11. Thus, the tertiary air is heated to hightemperature while it passes through the tertiary air ducts 35. Thisheated tertiary air is introduced into the secondary combustion chamber13. For this reason, combustion reaction of the gas in the secondarycombustion chamber 13 is further promoted, thereby improving combustionperformance. That is, since the gas burnt in the primary combustionchamber 11 and the hot tertiary air are mixed, combustion reactioneasily occurs and complete combustion is promoted. This further improvescombustion performance.

Since the baffle plate 41 is provided at the combustion gas vent 37 ofthe combustor 7, the combustion gas in the secondary combustion chamber13 is discharged from the center discharge hole 47 and the peripherydischarge holes 49. As a result, a difference in temperature between thecenter part and the peripheral part of the combustion gas is decreased.That is, the temperature of the combustion gas discharged from thecombustor 7 is uniformed.

In this embodiment, since the center discharge hole 47 is formed to besmaller than the periphery discharge hole 49, most of the combustion gasis discharged from the periphery discharge holes 49 and a small amountof the combustion gas is discharged from the center discharge hole 47.For this reason, the combustion gas easily spreads over the dischargedwarm air. Thus, a difference in temperature between the center part andthe peripheral part of the warm air becomes small.

Since the combustion gas is discharged from the periphery dischargeholes 49 at the side of the periphery of the combustion gas vent 37,even when a large amount of the combustion gas and the burning flameoccur in the primary combustion chamber 11 and the secondary combustionchamber 13, they are mixed with the peripheral air in the vicinity ofthe combustion gas vent 37, thereby that the burning flame is difficultto go outwards. Therefore, since the baffle plate 41 also suppressesburst-out of the burning flame, safety of the combustion device isimproved.

The present invention is not limited to the above-mentioned embodimentsand can be carried out according to the other aspects by makingappropriate modifications. The gas combustion device 1 in accordancewith this embodiment can be used as the gas combustion device such as ahair drier and a heat gun used for compression operation of aheat-shrinkable tube, drying, adhesion, fusing and soldering and theother gas combustion devices such as the other appliances.

INDUSTRIAL APPLICABILITY

According to the present invention, since the baffle member is providedat the combustion gas vent of the combustor, the temperature of thecombustion gas discharged from the combustor can be uniformed andburst-out of the burning flame can be prevented.

Further, since the combustion gas is discharged from center dischargehole 47 and the periphery discharge holes 49, respectively, a differencein temperature between the center part and the peripheral part of thecombustion gas becomes small. Furthermore, even when a large amount ofthe combustion gas and the burning flame occurs, since the combustiongas discharged from the periphery discharge holes is mixed with theperipheral air in the vicinity of the combustion gas vent, the burningflame can be prevented from going outwards.

Furthermore, since most of the combustion gas is discharged from theperiphery discharge holes and a small amount of the combustion gas isdischarged from the center discharge hole, the combustion gas easilyspreads over the discharged warm air and a difference in temperaturebetween the center part and the peripheral part of the warm air becomessmall.

1. A gas combustion device comprising: a combustion chamber for burninggas supplied from a gas source therein; a combustion gas vent fordischarging combustion gas burnt in the combustion chamber; and a bafflemember for adjusting distribution the combustion gas discharged from thecombustion gas vent which is arranged at the combustion gas vent.
 2. Agas combustion device of claim 1, wherein the baffle member furthercomprises a center discharge hole for discharging the combustion gas inthe combustion chamber from about the center of the combustion gas ventand periphery discharge holes arranged on the periphery of the centerdischarge hole for discharging the combustion gas from the side of theinner wall of the combustion chamber.
 3. A gas combustion device ofclaim 2, wherein the center discharge hole is formed to be smaller thanthe periphery discharge hole.